Chickens and Eggs

The other day my step-cousin and I tried to solve the chicken-and-egg question, from an evolutionary one-of-them-must-have-come-first perspective:

Assuming that there is some (probably arbitrary) dividing line in the evolutionary tree between pre-chicken and chicken, then there must have been a "first chicken" at some point - let's call her Lucy. Lucy's parents were, by definition, not chickens, but Lucy's mother laid an egg containing a chicken (by some lucky mutation or something). Lucy then must have laid her own egg, which not only (I think it's safe to assume) also contained a chicken, but additionally was laid by a chicken. So which egg are we talking about? This reveals an ambiguity in the original question. The question is

We must insist that the egg be specific to chickens, or else it's a silly question (the egg came first, whenever the first egg-laying species evolved, probably long before chickens). So we can state the question more clearly: But if we try to answer this question, we run into the ambiguity hinted at earlier, which is specifically: And once we choose one or the other, the answer is obvious - either the chicken came first (because the first egg was the egg laid by Lucy), or the egg came first (because the first egg was the egg Lucy hatched from), respectively.

The question's not so interesting anymore. So since we're thinking about evolutionary progression, how about this question: